This invention relates generally to the glass bending art and, more particularly, to press bending apparatus incorporating a novel vertically adjustable mechanism for positioning a lower female press member with respect to an upper male press member.
Curved glass sheets have become increasingly popular for use as glazing enclosures for automobiles and the like. A number of different curvatures is encountered as the degree of curvature of the flat glass sheets is dictated by the configuration and size of the openings in the overall design of different styles of automotive vehicles.
In the manufacture of curved glass sheets in large quantities, one common method of producing curved, tempered sheets of glass is heating flat sheets of glass to their softening temperature, pressing the softened sheets to the desired curvature between complemental shaping surfaces and then rapidly chilling the bent sheets in a controlled manner to a temperature below the annealing range of the glass. Generally, these operations are carried out successively while the sheets of glass are being advanced substantially continuously on a conveyor system along a horizontal path including a heating area, a bending area, and a chilling or tempering area whereby the heat initially imparted to each sheet to bring it to the proper bending temperature can also be utilized in the final heat treating or tempering operation.
The above referred to complemental shaping surfaces are formed on opposed press members each mounted on a supporting platen. The press members and the respective platens are normally located one above and one below the horizontal path of movement of the glass sheets to receive the latter therebetween, and are movable relative towards and away from each other for pressing the sheets into the desired shape. Generally, a hydraulic actuator is employed for raising the lower platen and press member upwardly to engage and lift a heated glass sheet off the conveyor system out of such horizontal path and press the same against the shaping surface of the opposed or upper press member.
Conventionally, a variety of curved glazing enclosures are run over a common production line and the fluid actuator has been mounted on a stationary member and its length of stroke has been determined by the depth of curvature of the particular style of glazing enclosure being produced. Accordingly, each time a glazing enclosure having a substantially different depth of curvature is to be produced, it is necessary to replace the fluid actuator with one having a different length of stroke to accommodate the depth of curvature of the new glazing enclosure. Not only is this changing of the fluid actuator time consuming, but the repeated connecting and disconnecting of the fluid lines of the actuator results in premature wear and leakage and eventual replacement of the fluid actuator.